Thinking Critically With Psychological Science Chapter 1: Thinking Critically With Psychological Science

Limits of Intuition While intuition is important, we may often rely too much on our “gut feelings” when making important, even dangerous decisions.

Hindsight Bias is the “I-knew-it-all-along” phenomenon. After learning the outcome of an event, many people believe they could have predicted that very outcome. We only knew the dot.com stocks would plummet after they actually did plummet.

Overconfidence Sometimes we think we know more than we actually know. Anagram How long do you think it would take to unscramble these anagrams? WREAT WATER ETYRN ENTRY People said it would take about 10 seconds, yet on average they took about 3 minutes. GRABE BARGE

The Scientific Attitude The scientific attitude is composed of curiosity (passion for exploration), skepticism (doubting and questioning) and humility (ability to accept responsibility when wrong). Preview Question 2: What are the three main components of scientific attitude?

Critical thinking does not accept arguments and conclusions blindly. It examines assumptions, discerns hidden values, evaluates evidence and assesses conclusions.

For example, low self-esteem contributes to depression. Theory A theory is an explanation that integrates principles and organizes and predicts behavior or events. For example, low self-esteem contributes to depression.

People with low self-esteem are apt to feel more depressed. Hypothesis A hypothesis is a testable prediction, often prompted by a theory, to enable us to accept, reject or revise the theory. People with low self-esteem are apt to feel more depressed.

Research Observations Research would require us to administer tests of self-esteem and depression. Individuals who score low on a self-esteem test and high on a depression test would confirm our hypothesis.

Research Process

Is language uniquely human? Description Case Study A technique in which one person is studied in depth to reveal underlying behavioral principles. Preview Question 4: How do psychologists observe and describe behavior? Susan Kuklin/ Photo Researchers Is language uniquely human?

Survey A technique for ascertaining the self-reported attitudes, opinions or behaviors of people usually done by questioning a representative, random sample of people.

Wording can change the results of a survey. Wording Effects Wording can change the results of a survey. Q: As you know, the term Holocaust usually refers to the killing of millions of Jews in Nazi death camps during World War II. Does it seem possible or does it seem impossible to you that the Nazi extermination of the Jews never happened?

Survey Random Sampling If each member of a population has an equal chance of inclusion into a sample, it is called a random sample (unbiased). If the survey sample is biased, its results are not valid. The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.

Naturalistic Observation Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation. Courtesy of Gilda Morelli

Descriptive Methods Summary Case studies, surveys, and naturalistic observation describe behaviors.

(positive or negative) Correlation When one trait or behavior accompanies another, we say the two correlate. Indicates strength of relationship (0.00 to 1.00) Correlation coefficient r = + 0.37 Correlation Coefficient is a statistical measure of the relationship between two variables. It reveals the extent to which two things relate. Preview Question 5: What are positive and negative correlations, and why do they enable prediction but not cause-effect explanation? Indicates direction of relationship (positive or negative)

Scatterplots Perfect positive correlation (+1.00) Scatterplot is a graph comprised of points that are generated by values of two variables. The slope of the points depicts the direction, while the amount of scatter depicts the strength of the relationship.

Scatterplots Perfect negative correlation (-1.00) No relationship (0.00) The Scatterplot on the left shows a negative correlation, while the one on the right shows no relationship between the two variables.

Correlation and Causation Correlation does not mean causation! or

Disconfirming evidence Illusory Correlation The perception of a relationship where no relationship actually exists. Parents conceive children after adoption. Confirming evidence Disconfirming evidence Do not adopt Adopt Do not conceive Conceive Preview Question 6: What are illusory correlations? Michael Newman Jr./ Photo Edit

Given random data, we look for order and meaningful patterns. Order in Random Events Given random data, we look for order and meaningful patterns. Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.

Order in Random Events Given large numbers of random outcomes, a few are likely to express order. Jerry Telfer/ San Francisco Chronicle Angelo and Maria Gallina won two California lottery games on the same day.

Exploring Cause & Effect Experimentation Exploring Cause & Effect Many factors influence our behavior. Experiments (1) manipulate factors that interest us, while other factors are kept under (2) control. Effects generated by manipulated factors isolate cause and effect relationships.

Double-Blind Procedure Evaluating Therapies Double-Blind Procedure In evaluating drug therapies, patients and experimenter’s assistants should remain unaware of which patients had the real treatment and which patients had the placebo treatment.

Evaluating Therapies Random Assignment Assigning participants to experimental (breast-fed) and control (formula-fed) conditions by random assignment minimizes pre-existing differences between the two groups.

Independent Variable An independent variable is a factor manipulated by the experimenter. The effect of the independent variable is the focus of the study. For example, when examining the effects of breast feeding upon intelligence, breast feeding is the independent variable.

Dependent Variable A dependent variable, the variable which is measured, is a factor that may change in response to an independent variable. In psychology, it is usually a behavior or a mental process. For example, in our study on the effect of breast feeding upon intelligence, intelligence is the dependent variable.

A summary of steps during experimentation.

Statistical Reasoning in Everyday Life Doubt big, round, undocumented numbers as they can be misleading and before long, become public misinformation. Apply simple statistical reasoning in everyday life to think smarter!

Describing Data A meaningful description of data is important in research. Misrepresentation may lead to incorrect conclusions. Preview Question 8: How can we describe data with measures of central tendency and variation?

Measures of Central Tendency Mode: The most frequently occurring score in a distribution. Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by the number of scores that were added together. Median: The middle score in a rank-ordered distribution.

Measures of Central Tendency A Skewed Distribution

Measures of Variation Range: The difference between the highest and lowest scores in a distribution. Standard Deviation: A computed measure of how much scores vary around the mean. “Normal Curve”

Illusion of Control That chance events are subject to personal control is an illusion of control fed by: Illusory Correlation: the perception of a relationship where no relationship actually exists. Regression Toward the Mean: the tendency for extremes of unusual scores or events to regress toward the average.

When is an Observed Difference Reliable? Making Inferences When is an Observed Difference Reliable? Representative samples are better than biased samples. Less-variable observations are more reliable than more variable ones. More cases are better than fewer cases. Preview Question 9: What principles can guide our making generalizations from samples and deciding whether differences are significant?

When is a Difference Significant? Making Inferences When is a Difference Significant? When sample averages are reliable and the difference between them is relatively large, we say the difference has statistical significance. It is probably not due to chance variation.

Is psychology free of value judgments?